Pub Date : 2022-12-12DOI: 10.1109/JMMCT.2022.3228281
Saurabh S. Sawant;Zhi Yao;Revathi Jambunathan;Andrew Nonaka
Modeling and characterization of electromagnetic wave interactions with microelectronic devices to derive network parameters has been a widely used practice in the electronic industry. However, as these devices become increasingly miniaturized with finer-scale geometric features, computational tools must make use of manycore/GPU architectures to efficiently resolve length and time scales of interest. This has been the focus of our open-source solver, ARTEMIS (Adaptive mesh Refinement Time-domain ElectrodynaMIcs Solver), which is performant on modern GPU-based supercomputing architectures while being amenable to additional physics coupling. This work demonstrates its use for characterizing network parameters of transmission lines using established techniques. A rigorous verification and validation of the workflow is carried out, followed by its application for analyzing a transmission line on a CMOS chip designed for a photon-detector application. Simulations are performed for millions of timesteps on state-of-the-art GPU resources to resolve nanoscale features at gigahertz frequencies. The network parameters are used to obtain phase delay and characteristic impedance that serve as inputs to SPICE models. The code is demonstrated to exhibit ideal weak scaling efficiency up to 1024 GPUs and 84% efficiency for 2048 GPUs, which underscores its use for network analysis of larger, more complex circuit devices in the future.
{"title":"Characterization of Transmission Lines in Microelectronic Circuits Using the ARTEMIS Solver","authors":"Saurabh S. Sawant;Zhi Yao;Revathi Jambunathan;Andrew Nonaka","doi":"10.1109/JMMCT.2022.3228281","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3228281","url":null,"abstract":"Modeling and characterization of electromagnetic wave interactions with microelectronic devices to derive network parameters has been a widely used practice in the electronic industry. However, as these devices become increasingly miniaturized with finer-scale geometric features, computational tools must make use of manycore/GPU architectures to efficiently resolve length and time scales of interest. This has been the focus of our open-source solver, ARTEMIS (Adaptive mesh Refinement Time-domain ElectrodynaMIcs Solver), which is performant on modern GPU-based supercomputing architectures while being amenable to additional physics coupling. This work demonstrates its use for characterizing network parameters of transmission lines using established techniques. A rigorous verification and validation of the workflow is carried out, followed by its application for analyzing a transmission line on a CMOS chip designed for a photon-detector application. Simulations are performed for millions of timesteps on state-of-the-art GPU resources to resolve nanoscale features at gigahertz frequencies. The network parameters are used to obtain phase delay and characteristic impedance that serve as inputs to SPICE models. The code is demonstrated to exhibit ideal weak scaling efficiency up to 1024 GPUs and 84% efficiency for 2048 GPUs, which underscores its use for network analysis of larger, more complex circuit devices in the future.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-16DOI: 10.1109/JMMCT.2022.3222529
S. R. Naga Praneeth;Bhim Singh
When dealing with electromechanical system modelling, numerical challenges are inevitable. Especially when working with moving conductor problems, such as rotational or linear motors, special care needs to be taken for the air-gap region. Railguns air region is one more addition to this modelling problem. The air region necessitates either remeshing or a custom mesh topology. In addition, the production of air mesh for conductors with complicated shapes has its own difficulties. The air mesh requirement may be reduced by using the finite element-boundary element (FE-BE) technique. Boundary elements for air mesh and finite elements for conductors allow for the creation of models with moving conductors and makes model production easier and quicker. This paper investigates the changes observed in the railgun's electrical and mechanical parameters through the finite element-boundary element simulation approach when the geometry of the augmentation rails in a railgun is changed. Tapering and filleting are two geometry changes implemented on the augmenting rails of an electromagnetic railgun. Designed railgun variants are investigated using LS-Dyna software. A new formulation for breech voltage in augmented electromagnetic railguns is derived to calculate barrel efficiency. Four configurations of augmented electromagnetic railguns are analyzed, emphasizing force profile, inductance gradient, and motional-emf ( $iL^{prime }v$ ). One of the new configurations has resulted in an improvement in the force profile during the initial stages of the launch by 8.8%, and the armature's final muzzle velocity has improved by 7%.
{"title":"Finite Element-Boundary Element Method Based Simulations of Electromagnetic Railgun in Augmented Configurations","authors":"S. R. Naga Praneeth;Bhim Singh","doi":"10.1109/JMMCT.2022.3222529","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3222529","url":null,"abstract":"When dealing with electromechanical system modelling, numerical challenges are inevitable. Especially when working with moving conductor problems, such as rotational or linear motors, special care needs to be taken for the air-gap region. Railguns air region is one more addition to this modelling problem. The air region necessitates either remeshing or a custom mesh topology. In addition, the production of air mesh for conductors with complicated shapes has its own difficulties. The air mesh requirement may be reduced by using the finite element-boundary element (FE-BE) technique. Boundary elements for air mesh and finite elements for conductors allow for the creation of models with moving conductors and makes model production easier and quicker. This paper investigates the changes observed in the railgun's electrical and mechanical parameters through the finite element-boundary element simulation approach when the geometry of the augmentation rails in a railgun is changed. Tapering and filleting are two geometry changes implemented on the augmenting rails of an electromagnetic railgun. Designed railgun variants are investigated using LS-Dyna software. A new formulation for breech voltage in augmented electromagnetic railguns is derived to calculate barrel efficiency. Four configurations of augmented electromagnetic railguns are analyzed, emphasizing force profile, inductance gradient, and motional-emf (\u0000<inline-formula><tex-math>$iL^{prime }v$</tex-math></inline-formula>\u0000). One of the new configurations has resulted in an improvement in the force profile during the initial stages of the launch by 8.8%, and the armature's final muzzle velocity has improved by 7%.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49950114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-14DOI: 10.1109/JMMCT.2022.3221835
Ozlem Ozgun;Raj Mittra;Mustafa Kuzuoglu
This paper presents an approach for evaluating the Sommerfeld integrals in the spectral domain, whose integrands typically show an oscillatory and slowly decaying behavior at high frequencies, e.g., in the mm-wave regime. It is well known that these integrals arise in the representations of the dyadic Green's functions of layered media and efficient computation of these Green's functions is key to rapid CEM modeling of patch antennas and printed circuits designed for 5G applications in the mm-wave range. The underlying concept of the approach is to partition the spectral domain representation of a Green's function into multiple domains and to represent the envelope of the integrand in each domain with a few exponentials such that the integrals in these domains can be evaluated analytically very efficiently and accurately in a numerically stable manner. Additionally, a new interpolation strategy is proposed in this work to decrease the matrix fill time in the MoM solution of the integral equations whose kernels contain Green's functions mentioned above. The performance enhancement realized by using the approaches is demonstrated through several illustrative examples.
{"title":"An Efficient Numerical Approach for Evaluating Sommerfeld Integrals Arising in the Construction of Green's Functions for Layered Media","authors":"Ozlem Ozgun;Raj Mittra;Mustafa Kuzuoglu","doi":"10.1109/JMMCT.2022.3221835","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3221835","url":null,"abstract":"This paper presents an approach for evaluating the Sommerfeld integrals in the spectral domain, whose integrands typically show an oscillatory and slowly decaying behavior at high frequencies, e.g., in the mm-wave regime. It is well known that these integrals arise in the representations of the dyadic Green's functions of layered media and efficient computation of these Green's functions is key to rapid CEM modeling of patch antennas and printed circuits designed for 5G applications in the mm-wave range. The underlying concept of the approach is to partition the spectral domain representation of a Green's function into multiple domains and to represent the envelope of the integrand in each domain with a few exponentials such that the integrals in these domains can be evaluated analytically very efficiently and accurately in a numerically stable manner. Additionally, a new interpolation strategy is proposed in this work to decrease the matrix fill time in the MoM solution of the integral equations whose kernels contain Green's functions mentioned above. The performance enhancement realized by using the approaches is demonstrated through several illustrative examples.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49950115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-09DOI: 10.1109/JMMCT.2022.3220716
Zi-Liang Liu;Chao-Fu Wang
A physics-based automatic target recognition (ATR) technique is developed to accurately identify small features located in highly similar structures with electromagnetic (EM) scattering data. Automatic target recognition is important due to its widely practical applications. The traditional ATR is usually based on images produced from EM scattering data and sophisticated algorithms. Wideband angular and frequency sweeps are necessary to generate sufficient EM scattering data to produce images with high resolution for the imagery-based ATR to obtain correct recognition results, especially for multiscale structures with small local features. These seriously limit the efficiency of the imagery-based ATR and its practicability. To implement ATR more efficiently, we turn to the physics-based ATR and employ principal component analysis (PCA). The physics-based ATR with PCA can exactly classify objects of different types with one-frequency scattering data and avoid expensive frequency sweeps. However, the pre-existing average feature center (AFC) criterion model for PCA in the literature can only distinguish objects with significant differences and fails to recognize small features located in highly similar structures. Hence, an improved classification criterion for PCA is proposed to precisely identify highly similar structures with different small features. Some numerical examples illustrate the satisfactory performance of the proposed technique.
{"title":"Physics-Based Automatic Recognition of Small Features Located in Highly Similar Structures With Electromagnetic Scattering Data","authors":"Zi-Liang Liu;Chao-Fu Wang","doi":"10.1109/JMMCT.2022.3220716","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3220716","url":null,"abstract":"A physics-based automatic target recognition (ATR) technique is developed to accurately identify small features located in highly similar structures with electromagnetic (EM) scattering data. Automatic target recognition is important due to its widely practical applications. The traditional ATR is usually based on images produced from EM scattering data and sophisticated algorithms. Wideband angular and frequency sweeps are necessary to generate sufficient EM scattering data to produce images with high resolution for the imagery-based ATR to obtain correct recognition results, especially for multiscale structures with small local features. These seriously limit the efficiency of the imagery-based ATR and its practicability. To implement ATR more efficiently, we turn to the physics-based ATR and employ principal component analysis (PCA). The physics-based ATR with PCA can exactly classify objects of different types with one-frequency scattering data and avoid expensive frequency sweeps. However, the pre-existing average feature center (AFC) criterion model for PCA in the literature can only distinguish objects with significant differences and fails to recognize small features located in highly similar structures. Hence, an improved classification criterion for PCA is proposed to precisely identify highly similar structures with different small features. Some numerical examples illustrate the satisfactory performance of the proposed technique.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49950117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-25DOI: 10.1109/JMMCT.2022.3216642
Khadijeh Masumnia-Bisheh;Cynthia Furse
This study evaluates the variance of specific absorption rate (SAR) due to expected variance in the dielectric properties of tissues in a 3D anatomical human head model exposed to a half-wave dipole antenna at 835 and 1900 MHz. Stochastic finite difference time domain (S-FDTD) is applied to calculate variations in the local SAR, and the 1- and 10-gram averaged SAR values. These are also compared at 835 MHz to variations found from Monte Carlo FDTD. It is found that for both frequencies dielectric property variance results in a variance of peak 1- or 10-gram SAR of approximately 30% to 55% of the mean SAR, depending on the frequency. These results show that to reach 95% confidence with the calculated SAR values for evaluating exposure guidelines, statistical variations in tissue electrical properties must be taken into account.
{"title":"Variability in Specific Absorption Rate From Variation in Tissue Properties","authors":"Khadijeh Masumnia-Bisheh;Cynthia Furse","doi":"10.1109/JMMCT.2022.3216642","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3216642","url":null,"abstract":"This study evaluates the variance of specific absorption rate (SAR) due to expected variance in the dielectric properties of tissues in a 3D anatomical human head model exposed to a half-wave dipole antenna at 835 and 1900 MHz. Stochastic finite difference time domain (S-FDTD) is applied to calculate variations in the local SAR, and the 1- and 10-gram averaged SAR values. These are also compared at 835 MHz to variations found from Monte Carlo FDTD. It is found that for both frequencies dielectric property variance results in a variance of peak 1- or 10-gram SAR of approximately 30% to 55% of the mean SAR, depending on the frequency. These results show that to reach 95% confidence with the calculated SAR values for evaluating exposure guidelines, statistical variations in tissue electrical properties must be taken into account.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49950022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seawall engineering is essential in preventing typhoon storm surge disasters in coastal areas. Usually, the engineering measure of throwing the stone to form a riprap layer is adopted to enhance seawall stability and anti-erosion property. Determining the thickness of the riprap layer is an essential step in the evaluation of engineering measurement, and the key is to determine the burial depth of the bottom boundary of the riprap. A seawall is taken as the research object. The propagation process of the electromagnetic wave in the seawall is simulated by the finite difference time domain (FDTD) method, the propagation law and profile response characteristics of the electromagnetic wave are obtained, and the method's feasibility is confirmed theoretically. Further field test and drilling detection results are used to calibrate the electromagnetic wave velocity, and the top and bottom interface of the riprap layer is divided, which provides a basis for the measurement of the riprap body.
{"title":"Numerical Simulation and Experiment for the Bottom Boundary of Riprap of Seawall by GPR","authors":"Xiongwu Hu;Bingqing Kong;Xiaoyi Jiang;Guanqun Zhou;Lei Tan;Hu Xu","doi":"10.1109/JMMCT.2022.3215804","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3215804","url":null,"abstract":"Seawall engineering is essential in preventing typhoon storm surge disasters in coastal areas. Usually, the engineering measure of throwing the stone to form a riprap layer is adopted to enhance seawall stability and anti-erosion property. Determining the thickness of the riprap layer is an essential step in the evaluation of engineering measurement, and the key is to determine the burial depth of the bottom boundary of the riprap. A seawall is taken as the research object. The propagation process of the electromagnetic wave in the seawall is simulated by the finite difference time domain (FDTD) method, the propagation law and profile response characteristics of the electromagnetic wave are obtained, and the method's feasibility is confirmed theoretically. Further field test and drilling detection results are used to calibrate the electromagnetic wave velocity, and the top and bottom interface of the riprap layer is divided, which provides a basis for the measurement of the riprap body.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49950023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-13DOI: 10.1109/JMMCT.2022.3211784
Javier Jair Pazos;Matthew C. Miller;Jeff Phillips;Eric Miller;Tim McDonald;Jennifer Kitaygorsky
Electromagnetic fields in representative spacecraft cavities were successfully predicted using finite-difference time-domain and power balance computational tools. Results were validated with measurements of two test articles, showing excellent correlation in shielding effectiveness from 300 MHz to 18 GHz. The validated tools were then extended to predict fields inside representative, to-scale payload fairings including common systems and components like satellite payloads, antennas, acoustic blankets, and a cable harness. Various computational techniques were used to compare their speed and accuracy. Ultimately, we conclude that a multi-fidelity approach – combining full-wave, statistical, and hybrid solutions – is beneficial and necessary for complex and large cavity problems. The tools and techniques presented here can serve as part of a toolkit to rapidly estimate shielding effectiveness, the impact of payloads, and overall fields in spacecraft cavities.
{"title":"Estimating Fields in Spacecraft Cavities: Experimental Validation and Optimization of Finite-Difference Time-Domain and Power Balance Computational Tools","authors":"Javier Jair Pazos;Matthew C. Miller;Jeff Phillips;Eric Miller;Tim McDonald;Jennifer Kitaygorsky","doi":"10.1109/JMMCT.2022.3211784","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3211784","url":null,"abstract":"Electromagnetic fields in representative spacecraft cavities were successfully predicted using finite-difference time-domain and power balance computational tools. Results were validated with measurements of two test articles, showing excellent correlation in shielding effectiveness from 300 MHz to 18 GHz. The validated tools were then extended to predict fields inside representative, to-scale payload fairings including common systems and components like satellite payloads, antennas, acoustic blankets, and a cable harness. Various computational techniques were used to compare their speed and accuracy. Ultimately, we conclude that a multi-fidelity approach – combining full-wave, statistical, and hybrid solutions – is beneficial and necessary for complex and large cavity problems. The tools and techniques presented here can serve as part of a toolkit to rapidly estimate shielding effectiveness, the impact of payloads, and overall fields in spacecraft cavities.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49950021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-30DOI: 10.1109/JMMCT.2022.3211178
Yang Zhong;Peter Renner;Weiping Dou;Geng Ye;Jiang Zhu;Qing Huo Liu
To facilitate the antenna design with the aid of computer, one of the practices in consumer electronic industry is to model and optimize antenna performances with a simplified antenna geometric scheme. The ease of handling multi-dimensional optimization problems and the less dependence on the engineers' knowledge and experience are the key to achieve the popularity of simulation-driven antenna design and optimization for the industry. In this paper, we introduce a flexible geometric scheme with the concept of mesh network that can form any arbitrary shape by connecting different nodes. For such problems with high dimensional parameters, we propose a machine learning based generative method to assist the searching of optimal solutions. It consists of discriminators and generators. The discriminators are used to predict the performance of geometric models, and the generators to create new candidates that will pass the discriminators. Moreover, an evolutionary criterion approach is proposed for further improving the efficiency of our method. Finally, not only optimal solutions can be found, but also the well trained generators can be used to automate future antenna design and optimization. For a dual resonance antenna design, our proposed method is better than the other mature algorithms.
{"title":"A Machine Learning Generative Method for Automating Antenna Design and Optimization","authors":"Yang Zhong;Peter Renner;Weiping Dou;Geng Ye;Jiang Zhu;Qing Huo Liu","doi":"10.1109/JMMCT.2022.3211178","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3211178","url":null,"abstract":"To facilitate the antenna design with the aid of computer, one of the practices in consumer electronic industry is to model and optimize antenna performances with a simplified antenna geometric scheme. The ease of handling multi-dimensional optimization problems and the less dependence on the engineers' knowledge and experience are the key to achieve the popularity of simulation-driven antenna design and optimization for the industry. In this paper, we introduce a flexible geometric scheme with the concept of mesh network that can form any arbitrary shape by connecting different nodes. For such problems with high dimensional parameters, we propose a machine learning based generative method to assist the searching of optimal solutions. It consists of discriminators and generators. The discriminators are used to predict the performance of geometric models, and the generators to create new candidates that will pass the discriminators. Moreover, an evolutionary criterion approach is proposed for further improving the efficiency of our method. Finally, not only optimal solutions can be found, but also the well trained generators can be used to automate future antenna design and optimization. For a dual resonance antenna design, our proposed method is better than the other mature algorithms.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49950118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-23DOI: 10.1109/JMMCT.2022.3209071
Kaiqi Yan;Ana Vukovic;Phillip Sewell;Trevor M. Benson
The transmission-line modelling (TLM) method has been widely applied to many areas including electromagnetic and heat conduction problems. Its unstructured version, unstructured TLM (UTLM), however, has not hitherto been fully exploited in thermal diffusion problems. This paper derives in detail a thermal UTLM scheme to solve the two-dimensional diffusion equation numerically based on the optimal Delaunay triangular (ODT) mesh.
{"title":"Two-Dimensional Thermal Diffusion Equation Solver Based on Unstructured Transmission-Line Modelling and Optimal Delaunay Triangular Meshes","authors":"Kaiqi Yan;Ana Vukovic;Phillip Sewell;Trevor M. Benson","doi":"10.1109/JMMCT.2022.3209071","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3209071","url":null,"abstract":"The transmission-line modelling (TLM) method has been widely applied to many areas including electromagnetic and heat conduction problems. Its unstructured version, unstructured TLM (UTLM), however, has not hitherto been fully exploited in thermal diffusion problems. This paper derives in detail a thermal UTLM scheme to solve the two-dimensional diffusion equation numerically based on the optimal Delaunay triangular (ODT) mesh.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49950024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-07DOI: 10.1109/JMMCT.2022.3204722
Mohsen Eslami Nazari;Weimin Huang
A solution for electromagnetic (EM) scattering over a two-dimensional random rough surface (three-dimensional scattering problem) with large roughness height using the generalized functions approach is proposed in this paper. The EM field derivation incorporates rough surface profile with small-slope, a radiation source and involves all scattering orders of the scattered electric field (E-field) for high and moderate contrast media. Subsequently, the first-order scattered E-field is calculated using the Neumann series solution for transverse magnetic (TM) polarization. By considering pulsed dipole antenna and a two-dimensional Gaussian rough surface distribution with different root mean square heights and correlation lengths, the scattered E-field along with the radar cross-section is calculated. Using the result of the method of moments (MoM) as reference, a numerical evaluation of the solution for different roughness heights and contrast media demonstrates that the proposed solution is better than those of the small perturbation method (SPM), Kirchhoff approximation (KA) and small-slope approximation (SSA).
{"title":"EM Wave Scattering by Random Surfaces With Different Contrast and Large Roughness Heights","authors":"Mohsen Eslami Nazari;Weimin Huang","doi":"10.1109/JMMCT.2022.3204722","DOIUrl":"https://doi.org/10.1109/JMMCT.2022.3204722","url":null,"abstract":"A solution for electromagnetic (EM) scattering over a two-dimensional random rough surface (three-dimensional scattering problem) with large roughness height using the generalized functions approach is proposed in this paper. The EM field derivation incorporates rough surface profile with small-slope, a radiation source and involves all scattering orders of the scattered electric field (E-field) for high and moderate contrast media. Subsequently, the first-order scattered E-field is calculated using the Neumann series solution for transverse magnetic (TM) polarization. By considering pulsed dipole antenna and a two-dimensional Gaussian rough surface distribution with different root mean square heights and correlation lengths, the scattered E-field along with the radar cross-section is calculated. Using the result of the method of moments (MoM) as reference, a numerical evaluation of the solution for different roughness heights and contrast media demonstrates that the proposed solution is better than those of the small perturbation method (SPM), Kirchhoff approximation (KA) and small-slope approximation (SSA).","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49950266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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